This invention relates to a method for deleting and reintroducing individual yarns to a textile process wherein the method can feed any number and combination of yarns at any time.
Many fiber processes adjust the position of different yarns in a fabric to create special effects. For example, in handmade tapestries, yarns of different colors are locked into precise locations to create highly detailed images. In machine-made fabrics, many techniques have been developed to vary the yarn at each point of the surface. The techniques, although varied, can be divided into two groups: processes which adjust the relative geometry of different feed yarns and processes which vary feed yarn at any time.
Weaving is a typical process which can adjust the relative geometry of different feed yarns. This can be illustrated by considering the example of weaving a red warp with a white filling. The fabric will appear red where the warp yarn passes over the filling and white elsewhere. Knitting and tufting can create the same effect by hiding or "burying" the unwanted yarns within the fabric and placing the desired yarns on the surface. This method of changing color has the inherent disadvantage of wasting yarn, particularly when some colors appear on the surface infrequently. In addition, this method limits the number of colors that can be used since only a limited amount of yarn can be hidden at each location.
Several processes utilize the method of changing feed yarn at different locations. In weaving, this is done by changing the filling yarn supply at different picks along the fabric. In computer controlled embroidery, the machine can be stopped and automatically restrung with a different color thread to create highly detailed patterns.
In tufting, special machinery has been developed to automatically switch feed yarns to tufting needles to create patterns in carpets. The process of this invention provides a new method of changing feed yarns which overcomes some of the inherent problems of the existing processes. It has the advantages of switching yarns without stopping the process and of feeding a number of yarns simultaneously.